<?php
namespace App\Helper;


class UploadImgHelper
{
	private $src;
	private $image;
	private $imageinfo;
	private $percent=0.5;

	public function __construct($src, $percent=1)
    {
        $this->src = $src;
        $this->percent = $percent;
    }
    /**
     * 高清压缩图片
     * @param string $saveName  提供图片名（可不带扩展名，用源图扩展名）用于保存。或不提供文件名直接显示
     */
    public function compressImg($saveName=''){
    	$this->_openImage();
    	if(!empty($saveName)){
    		$this->_saveImage($saveName);  //保存
    	}else{
    		$this->_showImage();
    	}
    }
    /**
     * 内部：打开图片
     */
    public function _openImage(){
    	list($width, $height, $type, $attr) = getimagesize($this->src);
    	$this->imageinfo=[
    		'width'=>$width,
    		'height'=>$height,
    		'type'=>image_type_to_extension($type,false),
    		'attr'=>$attr
    	];
    	$fun = "imagecreatefrom".$this->imageinfo['type'];
    	$this->image = $fun($this->src);
    	$this->_thumpImage();
    }
    /**
     * 内部：操作图片
     */
    public function _thumpImage(){
    	$new_width = $this->imageinfo['width'] * $this->percent;
    	$new_height = $this->imageinfo['height'] * $this->percent;
    	$image_thump = imagecreatetruecolor($new_width,$new_height);
    	imagecopyresampled($image_thump,$this->image,0,0,0,0,$new_width,$new_height,$this->imageinfo['width'],$this->imageinfo['height']);
    	imagedestroy($this->image);
    	$this->image = $image_thump;
    }
    /**
     * 输出图片:保存图片则用saveImage()
     */
    public function _showImage(){
    	header('Content-Type: image/'.$this->imageinfo['type']);
    	$funcs = "image".$this->imageinfo['type'];
    	$funcs($this->image);
    }
    /**
     * 保存图片到硬盘：
     * @param  string $dstImgName  1、可指定字符串不带后缀的名称，使用源图扩展名 。2、直接指定目标图片名带扩展名。
     */
    public function _saveImage($dstImgName){
    	if(empty($dstImgName)) return false;
    	$allowImgs = ['.jpg', '.jpeg', '.png', '.bmp', '.wbmp','.gif'];   //如果目标图片名有后缀就用目标图片扩展名 后缀，如果没有，则用源图的扩展名
    	$dstExt =  strrchr($dstImgName ,".");
    	$sourseExt = strrchr($this->src ,".");
    	if(!empty($dstExt)) $dstExt =strtolower($dstExt);
    	if(!empty($sourseExt)) $sourseExt =strtolower($sourseExt);
    	//有指定目标名扩展名
    	if(!empty($dstExt) && in_array($dstExt,$allowImgs)){
    		$dstName = $dstImgName;
    	}elseif(!empty($sourseExt) && in_array($sourseExt,$allowImgs)){
    		$dstName = $dstImgName.$sourseExt;
    	}else{
    		$dstName = $dstImgName.$this->imageinfo['type'];
    	}
    	$funcs = "image".$this->imageinfo['type'];
    	$funcs($this->image,$dstName);
    }
    /**
     * 销毁图片
     */
    public function __destruct(){
    	imagedestroy($this->image);
    }
}
?>